Breechcase for firearm



June 3, 1969 s. MAILLARD BREECHCASE FOR FIREARM Filed April l, 1968 June 3, 1969 B. MAILLARD BREECHCASE FOR FIREARM .3 ars Sheet Filed April 1, 1968 www B. MAILLARD BREECHCASE Fon FIREARM June 3, 1969 Sheet Filed April l, 1968 .w .mwN

United States Patent O 54,210 Int. Cl. F41d 1/02, 5/02, 11/00 U.S. Cl. 89-199 9 Claims ABSTRACT F THE DISCLOSURE The breechcase comprises a portion of substantially rectangular cross-section having in one of its small sides an ejection passage for the empty cartridge cases, and in its two large sides introduction openings for the cartridges coming alternately from two feed mechanisms respectively. The breech mechanism, which reciprocates in the breechcase, is substantially cylindrical. A helical counter-recoil spring, of substantially the same external diameter as the breech mechanism, is provided between the breech mechanism and the rear of the breechcase. The breechcase has, at the level of the cartridge introduction openings, four guiding surfaces, situated on a common geometrical cylinder parallel to the axis of the gun barrel, for guiding the breech mechanism and the counter-recoil spring.

The present invention relates to firearms that are at least semi-automatic, in particular to automatic firearms of calibre advantageously comprised between 20 and 50 mm. Firearms of these types recock themselves automatically after each round, and the firing of the following round can either require an action on the part of the gunner (semi-automatic firearms) or not (automatic firearms).

The invention comprises principally the following features, taken separately or in any combination.

According to a first feature of the invention, a firearm comprises a substantially cylindrical breech mechanism adapted to be displaced in an alternating translatory movement in a breechcase having towards the rear an interior shape and an exterior shape which are substantially rectangular, this breechcase having in one of the small sides of its substantially rectangular cross-section an ejection passage for the ejection of the empty cartridge cases and in the two large sides of said cross-section introduction openings for the introduction of cartridges coming respectively .from two feed mechanisms which can be alternately put in firing position, a helical counter-recoil spring being provided between the breech mechanism and the rear part of the breechcase, the firearm being characterized by the fact that the part of the breechcase which is of substantially rectangular cross-section, has at the level of the cartridge introduction openings, four guiding surfaces for guiding the breech mechanism as well as for guiding the the counter-recoil spring whose exterior diameter is substantially equal to the exterior diameter of the breech mechanism, said guiding surfaces being situated on a common geometrical cylinder of revolution about an axis having the same direction as the axis of the barrel of the firearm.

According to a second feature of the invention, a Ifirearm is adapted to receive two feed mechanisms articulated on the breechcase of the firearm and controlled so that one of them is in firing position when the other is out of firing position vice-versa, each feed mechanism having a mechanism for advancing cartridges and for transmitting motion housed in the feed mechanism and a driving lmember adapted to be displaced in a direction substantially parallel to the axis of the barrel of the firearm, the firearm being characterized by the fact that it comprises for the two feed mechanisms a single motor member having alternating longitudinal motion connected to a recoiling part of the firearm and of form and position such that it meets, during its recoil motion, only the driving member of the feed mechanism that is in firing position.

According to a third feature of the invention, a firearm comprises at the interior of a breechcase, on the one hand, a sleeve to which the barrel of the firearm is fixed in a removable manner by a bayonet joint, and on the other hand, a nut which is screwed on the front of the breechcase and which serves for maintaining the sleeve in longitudinal direction towards the front and in transverse direction at the same time, connecting means being provided between the part of the barrel and/or the sleeve situated at the front of the nut and a zone situated at the rear of the sleeve between the sleeve and the breechcase, more particularly, the sleeve of this firearm being adapted to recoil with the barrel with respect to the breechcase and being guided in translation by said nut, the Ifirearm being characterized by the fact that the sleeve has two successive collars, namely a front collar whose diameter is equal to the interior diameter of the nut and which is disposed at the interior of this nut for maintaining the sleeve transversely with respect to the nut, and a rear collar whose diameter, which is greater than the diameter of the front collar, is equal to the interior diameter of the breechcase and which is disposed behind the nut for maintaining the sleeve longitudinally with respect to the nut and transversely with respect to the breechcase, and by the fact that the interior diameter of the nut is sufficiently large so that an intermediate element of said connecting means passes through the front collar without touching the nut, due to which it is possible to unscrew or screw the nut for dismantling or remantling the sleeve, without preliminary dismantling of the connecting means.

According to a fourth feature of the invention, a firearm has an ejection system comprising an extractor carried by the movable breech mechanism, and diametrically opposed, an ejector carried by the breechcase and cornprising at the front a transverse striking surface for the rear edge of the cartridge case to be ejected, which ejector is controlled by the breech mechanism in a manner to present said striking surface in the trajectory of this rear edge during the recoil of the breech mechanism, the firearm being characterized by the fact that the ejector comprises, at the Ifront of this striking surface, a projection adapted to strike transversely the lateral surface of the cartridge case, before the impact with the rear edge, in 'a manner to tip the cartridge case before this impact in the direction of the ejection passage, which attenuates the violence of said impact.

The present invention wil be clearly understood from the following specific description of a preferred embodiment of the invention, given, merely by way of example, with reference to the accompanying drawings, in which:

FIGURES 1 and 2 (both divided by a vertical broken line into two parts a and b intended to be considered end to end) show a rearm according to the present invention, respectively in vertical section and in horizontal section along II-II of FIGURE l;

FIGURES 3 and 4 are sections along the lines lII and IV respectively of FIGURE 1;

And FIGURE 5 illustrates the operation of the ejection system visible in FIGURE l.

The firearm shown in the drawings is a heavy machine gun of calibre between 20 and 30 mm., for example.

With regard to the firearm as a whole, it comprises a substantially cylindrical breech mechanism 1 adapted to be displaced in a translatory movement in a breechcase 2 having towards the rear an interior shape and an exterior shape which are substantially rectangular (see FIGURE 4), the small sides of this cross-section being designated by 3 and 4 and the large sides by 5 and 6. The breechcase 2 has, on the small side 3, an ejection passage 7 for the empty cartridge cases, and on the two large sides and 6, introduction openings 8 for the introduction o-f cartridges coming from two feed mechanisms 9 which can be alternately put into position for firing. A helical counter-recoil spring 10 is provided between the breech mechanism 1 and the rear part of the breechcase 2.

With regard to the breech mechanism 1, it is advantageously constructed according to the U.S. patent application filed on even date herewith by the present applicant for Breech Mechanism for Automatic or Semi- Automatic Arms. Such a breech mechanism comprises a breechblock 11 which is locked by rotation and which comprises on the one hand, at its front part, a cup-shaped recess 12 in which the rear ends (not shown) of the cartridges to be fired come into engagement, and on the other hand, exteriorly, locking lugs 13 which cooperate with lugs 14 formed on a sleeve 15, which receives the barrel 16 in a removable manner due to a bayonet joint 17. The breech mechanism 1 also comprises a casing 18, formed of two casing elements in the lform of shells separated approximately by the plane of FIGURE l. The casing 18 can slide without rotating in the breechcase 2 and is disposed around the breechblock 11. This breechblock passes through the casing 18 at the rear in a manner to cooperate with the usual breech damping device 19, situated at the rear of the breechcase 2. A spindle 20 passes through the breechblock 11 and is connected, at the interior of this breechblock, to the tiring pin 21, and, at the exterior of this breechblock, without play, to the casing 18. The lugs 13 of the breechblock 11 are situated on the same cylinder of revolution as a part 'at least of the exterior surface of the casing 18, which permits the breechblock 11 to be guided by the contact of the casing 18 and of at least some of its lugs 13 with the same surface (which will be more explicitly described hereafter). A spring 111 acting on the firing pin 21 tends to push the unit formed by the ring pin 21 and the casing 18 towards the front of the breechblock 11.

In order to transform into a rotary movement of the breechblock 11, the translatory movement which is produced between the casing 18 and this breechblock when the breechblock arrives substantially at the position of closing shown in FIGURES 1 and 2, the spindle 20 carries two cylindrical rollers 22 cooperating respectively with skews 22a formed in a cylindrical enlarged portion 23 of the breechblock 11.

At its exterior surface, the casing 18 carries two longitudinal projections 24 and 25 whose longitudinal lateral faces 24a and 25a cooperate with the interior faces of the small slides 3 and 4 of the breechcase 2 (see FIG- URE 4) to prevent the casing Ifrom turning at the interior of this breechcase. The projection 24 comprises a front face 24b adapted to cooperate with a seer 26 for stopping the breech mechanism in the open position. The projection 25 comprises a front face 26b adapted to cooperate, on the one hand, with an unlocking push-piece 27 (actuated in the manner described hereafterby tapping the gases in the barrel `16) which is provided for unlocking the breech mechanism 1 with respect to the breechcase 2, and on the other hand with a recocking device which permits the breechblock 11 to be brought back towards the rear after the breechblock has been stopped in the closing position. Such a recocking device can comprise a chain 218, one link of which carries a hook for the face 25b. The chain 28 is stretched between a front idler pinion 29 and a rear pinion 30 xed on a Spindle rigid with. a @rank 3.2. The projection 45 fur- 4 ther cooperates by the rear with an ejector 33, mounted on a transverse spindle 34, for the purpose of making it tip, the projection 25 having a longitudinal groove 25C for the passage of the ejector.

Between two of its lugs 13, the breechblock 11 carries an extractor 35, and on the diametrically opposed side, it has a groove 36, for the passage of the ejector 33, which leads into the cup-shaped recess 12. The extractor can be maintained in place by a leaf-spring 37.

To maintain the casing 18 imperatively in its extreme rear position with respect to the breechblock 11 during the reciprocating movement of the breech mechanism 1 inside the breechcase 2, a leaf-spring 38, carried by the breechblock 11, tends to project by its rear part against a bearing face 39 of the casing 18. An inclined surface 40, carried by the breechcase 2, can retract the leaf-spring 38 by acting on a push-piece 41 passing through the casing 18.

That being the case, according to a rst feature of the invention, the part 3-6 of the breechcase 2 that is of substantially rectangular cross-section has, at the level of the cartridge introduction openings 8, four guiding surfaces 42 for the breech mechanism 1 (casing 18 and lugs 13) as well as for the counter-recoil spring 10 whose exterior diameter is substantially equal to the diameter D of the breech mechanism, these guiding surfaces 42 being situated on a cylinder of revolution about an axis parallel to the axis X-X of the barrel 16 and generally coincident with this axis X-X. The trace of this cylinder on the plane of FIGURE 4 is coincident with the exterior contour of the casing 18 which is also the exterior contour of the spring 10.

According to an advantageous embodiment of this feature of the invention, the part of substantially rectangular cross-section 3-6 of the breechcase 2 is extended towards the front by a part 43 whose interior and exterior cross-sections are cylinders of revolution about the axis X-X of the barrel 16; the part 43 receives the sleeve 15 to which the barrel 16 is fixed in a removable manner; the annular space left free between the exterior of the sleeve 15 and the interior of the cylindrical part 43 of the breechcase 2 houses the control devices of the feed mechanism or mechanisms 9 (control devices which will be described hereafter), the damping devices for the recoil and the return to tiring position and the breech mechanism unlocking device with its push-piece 27.

The passage 7 and the openings y8 extend towards the front to the front end of the sides 3, `5 and 6. The small side 4 is approximatively tangent to the cylindrical part 43. This part and the elements of each large side 5 and 6 that exist on both sides (in the transverse direction) of the openings 8 are connected among themselves by transverse partitions I61 that render the breechcase 2 rigid and assure its Huid-tightness.

It is supposed in the following that the breechcase 2 is fixed and that the unit formed by the sleeve 15 and the barrel 16 can recoil with respect to this breechcase at the interior of which it is guided. The damping devices for the recoil and for the return to tiring position can be of two types, mechanical and hydraulic. The mechanical damping devices, which are five in number in the embodiment represented, each comprise a helical spring 44, coiled around a telescopic guide 45 parallel to the axis X-X of the barrel 16, which bears, at the front, against a collar 46 integral with the sleeve 15, and at the rear, against a ring 47 rigid with the breechcase 2. This ring 47 can be maintained against a shoulder 48 of the breechcase not only by the springs 44 but also by rods 49 fixed by one end to this ring, passing freely through the collar 46 and bearing by the other end on a nut 50 screwed on the front of the breechcase 2. The hydraulic damping devices, which are two in number in the embodiment represented, comprise oil dash-pots each comprising a cylinder 51 coupled to the ring 47 and a piston whose piston-rod 52 is coupled to the collar 46, although of course the pistons and cylinders can be iuterchanged.

The unlocking device, with its push-piece 27, for the breech mechanism 1 can comprise a cylinder 53, backed onto the collar 46, and a piston or plunger 54 rigid with the push-piece 27. The cylinder 53 is connected by a conduit 55, comprising a throttle device 56 (that is to say a body traversed by a channel whose cross-section permits the regulation of the operation of the device by constriction of the gases), to a `zone of the barrel 16 situated at a certain distance from the cartridge chamber 57. The unit formed by the push-piece 27 and the piston or plunger 54 is returned towards the front by a spring 58, the pushpiece 27 and this spring passing through the ring 47 through an opening visible at the bottom of FIGURE 1.

In the annular space left free between the exterior of the sleeve 15 and the interior of the cylindrical part 43, the damping devices for the recoil and for the return to liring position and the unlocking device for the breech mechanism 1 can occupy the lower sector, as shown in FIGURE 3, the unlocking device being advantageously placed in a manner to separate these damping devices into two approximatively symmetrical groups. In the space in question, a guiding key 59 can be disposed, riveted to the breechcase 2, and lying without play in grooves which pass through the collar 46 and the ring 47 parallel to the axis X-X thus preventing them from rotating about this axis. In particular, it will be understood that at the firing of a round, the starting of the rotation of the projectile, by penetration of the helical lands of the barrel 16 into the driving-band of the projectile, generates, by reaction, in the unit formed by the barrel and the sleeve 1S, a torque which is absorbed by the key 59, which prevents this unit from rotating at the interior of the breechcase 2.

To the rear of the introduction openings 8, the large sides 5 and 6 of the part of substantially rectangular crosssection of the breechcase 2 are closed by coaxial curved parts 60 whose interior diameter is equal to the diameter D of the breech mechanism 1 and which are adapted to render the breechcase 2 iluidtight and rigid, while guiding the breech mechanism 1 and the counter-recoil spring 10. In FIGURE 4, the central zone of the curved parts 60 can be seen through an opening 62 in the transverse partitions 61, the interior contour of these parts 60 being coincident with the exterior contour of the casing 18 (which is also the exterior controur of the spring The interior width indicated by the arrow a, between the large sides 5 and 6, is larger than the maximum diameter of the cartridge cases (so that these cartridge cases can pass through the passage 7) and smaller than, but as near as possible to the diameter D of the breech mechanism (to permit the curved parts 60 to be fitted in place).

The curved parts r60 are extended at the rear, beyond the part of substantially rectangular section 3-6, by two cylindrical sectors 63 provided with bayonet lugs 64 and adapted to receive a closing block 65 which serves as a support for the counter-recoil spring 10 and contains the damping device 19 of the breech mechanism. In addition to a cylindrical part y65a which fits partially on the sector 63, and a back which can be comprised by an element of the device 19, the block 65 can comprise at the front two radial wings 65b adapted to block off the zones of the part of substantially rectangular cross-section 3-6 which are not covered by the cylindrical part 65a.

At the interior of the part of substantially rectangular cross-section of the breechcase 2 and in the neighbourhood of the small sides 3 .and 4 of this cross-section, there can be disposed, at the exterior of the volume swept by the breech mechanism 1, supplementary mechanisms such as the Sear 26 and its damping spring 66, the ejector 33 and the recocking mechanism 28-30. A cam 67 serves to retract the sear 26 against the action of a spring 68.

It is advantageous to make the breechcase 2 carry externally, on one of the small sides of its substantially rectangular cross-section, for example on the side 4, at least one spindle or rod of articulation 69 for the alternate placing of the feed mechanisms 9 in firing position, and on the other small side 3, the mechanism controlling the rotation of the feed mechanisms about this rod 69.

With regard to the fastening and the control of the feed mechanisms 9, they are advantageously arranged as in my United States patent application Ser. No. 622,643 led Mar. 13, 1967. For this purpose, the two feed mechanisms 9 are mounted in a manner that they can rotate about an axis Y--Y parallel to the axis X-X of the barrel 16. The axis of rotation Y--Y is materialized by a hinge 70 assembled by the rod 69. The mechanisms 9, which are in general belt feed mechanisms, are each provided with a cover 71 which can rotate about a hinge 72, with respect to a casing 82 xed directly to the small side 4 of the breechcase 2, in order to permit the transverse introduction of the cartridge belt. Each cover is normally locked by a hook 73.

The mechanisms 9 are coupled by a fork 74 guided on the small side 3 in a manner that it can slide transversely with respect to the firearm. The fork 74 has slots 7S which each cooperate with a catch 76 rigid with the feed mechanism being considered. A slider 77, guided longitudinally on the small side 3, actuates a lever 78 which is carried by a spindle 79 passing through the slider through an elongated slot. This lever has a curved head 78a, in the form of a dovetail, which is engaged in a mortise 74a of the fork 74. When the gunner displaces the slider 77 longitudinally in one direction or the other, it rocks the lever 78 about the spindle 79 and displaces the fork 74 transversely (toward the left of FIGURE 4 if the position shown is the starting position), which puts out of action the feed mechanism 9 (at the left of FIG- URE 4) which was in lring position, and puts in action the other feed mechanism, by rocking about the rod 69.

Each feed mechanism 9 has a mechanism for belt advancement and for motion transmission housed in the casing 82 of the feed mechanism and a driving member adapted to be displaced in a direction substantially parallel to the axis X`X of the barrel 16 of the firearm. According to the embodiment represented in FIGURE 2, the belt .advancement mechanism comprises cartridgepushing pawls and the motion transmission mechanism for transmitting motion to these pawls is comprised by a lever 81 adapted to pivot about a spindle 83 and having a driving projection 84. The advancement mechanism can be of any type, for example as described in United States Patent No. 3,198,075. Furthermore, the driving member of the feed mechanism is comprised by a roller 85 which is carried by one of the arms of a twoarmed lever 86. The other arm of this lever carries a second roller 87 situated in the trajectory of the projection 84, the lever 86 pivoting about a spindle 88 parallel to the spindle 83. The arm of the lever 86 that carries the roller 85 is oriented in a manner such that this roller describes a circular arc practically identical with its tangent that s parallel to the axis X-X. It can be seen that, if the roller 85 is pushed towards the right of FIG- URE 2, it makes the lever 86 rock in the direction which raises the roller 87 with respect to the plane of FIGURE 2, which makes the lever 81 rock in a manner such that its free end is displaced in the same direction. At least one spring (not shown) assures the return of the levers 81 and 86 by maintaining the roller 87 n contact with the projection 84.

For two such feed mechanisms, according to a second feature of the invention, the firearm comprises a single motor member having alternating longitudinal movement and connected to a recoiling part of the firearm, this motor member having a form and a position such that it meets, during its active or recoil movement, only the driving member 85 of the feed mechanism 9 that is in 'firing position.

According to a particularly advantageous embodiment of this feature, the motor member has the form of a yfork 89 whose base 89a is oriented towards the front and cooperates with longitudinal guiding surfaces and whose two branches 89h cooperate by their rear part respectively and alternately with the driving members or rollers 85 of the feed mechanisms. The fork 89 has a transverse 89C interconnecting the base 89a and the branches 89b. In each casing 82, a passage 90 is provided opposite the roller 85 for the corresponding `brauch 89b. It can be seen in FIGURE 4 that the right feed mechanism, which is out of action, has its passage 90 out of the trajectory of the corresponding branch 89b, this branch passing freely into a notch 91 formed in the casing 82. On the contrary, the feed mechanism visible at the left of FIG- URE 4, which is in action, has its passage 90 just opposite the corresponding branch 89b, such that only this branch meets the roller 85 that is associated with it and can thus actuate the lfeed mechanism 9 that is n action.

It has been explained hereabove that the control mechanisms of the feed mechanism or feed mechanisms 9 were placed, with other members, in the annular space left free between the exterior of the sleeve and the interior of the cylindrical part 43 of the breechcase 2. These control mechanisms comprises essentially the fork 89, whose transverse 89e is curved to conform to the sector of the annular space that it occupies (see FIG- URE 3), as well as compression springs (with their guides) which are described hereafter.

As it has just been explained, the sleeve 15 essentially forms with the barrel 16 the recoiling part of the firearm whose breechcase 2 is fixed. The fork 89 is guided at the front by the collar 46 forming a part of the sleeve 15, due to a notch 92 through which the front end of the base 89a passes without appreciable lateral play. The front end of the base 89a can be maintained radially against the bottom of this notch by contact with the interior wall of the cylindrical part 43 of the breechcase 2, as can be seen at the top of FIGURE 1. Furthermore the fork 89 is guided at the rear by a member fixed with respect to the breechcase 2, this member being advantageously comprised by the ring 47. For this purpose, this ring can comprise a bore 93 parallel to the axis X--X and adapted to guide an extension 89d of the base 89a, situated towards the rear beyond the transverse 89e. The ring 47 can furthermore comprise a central bore 98 for guiding the rear of the sleeve 15. The base 89a can carry a shoulder 89e adpated to cooperate by abutment with the rear face of the collar 46 of the sleeve 15.

Between the fork 89 and the collar 46 acts at least one compression spring adapted to make the fork recoil with respect to the breechcase 2, abutment means being provided for bringing back the fork into firing position during the forward return of the recoiling part 15, 16 of the firearm.

As can be seen in FIGURES 2 and 3, two compression springs 94, each Wound around a telescopic guide 95 parallel to the axis X-X, can be disposed on both sides of the base 89a, these springs bearing at the rear against the transverse 89C of the fork.

The abutment means for bringing back the fork into firing position comprise, preferably, a double shoulder 96 provided at the end of the base 89a, in front of the collar 46, and adapted to abut against the front face of this collar.

FIGURE 3 shows that in front of this transverse the annular space defined hereabove receives the base 89a, four springs 94 with their guides 95, two hydraulic damping devices 51 and 52, five mechanical damping devices 44 and 45, and the unlocking device 53 and 54 for the breech mechanism. To the rear of the transverse 89e, the springs 94 with their guides 95 are absent and the base 89a is replaced by the branches 89h and the extension 89d.

The interior of the base 89a of the fork can be in the form of a cylinder forming part of a dash-pot regulator for regulating the recoil speed of the fork, this recoil being accompanied by the relaxation of the springs 94. For this purpose, the base 89a is provided with a bore 97, parallel to the axis X-X, in which two pistons 99 and 100 can slide which are mounted one behind the other, with a certain axial play, on a rod 101. This rod passes in a liquid-tight manner rearwardly through the bottom of the cylinder formed by the bore 97 and bears, preferably by the intermediary of the ring 47, against a stop 102 rigid with the breechcase 2. An annular sealing ring 103, disposed in a slidable manner about the rod 101, is pushed by a spring 104 towards the two pistons 99 and 100, and the space situated in the bore 97 in front of the sealing ring 103 is filled with oil. It can be seen that the spring 104 has the effect of maintaining in this space a pressure sufficient to push the rod 101 into contact with the stop 102 and permits, moreover, the sealing ring 103 to be displaced to compensate for the variations of volume of this space which are due to the larger or smaller penetration of the rod 101. Between the front piston 100 and the bore 97, play is provided which normally assures a constant speed of recoil of the fork 89 by passage of the oil from the front to the rear of this piston. The piston 99 carries elastic rings 105 which tend to separate the piston 100 from the piston 99. The piston 100 has channels 106 passing therethrough adapted to be blocked off by the neighbouring face of the piston 99 when the piston 99 is in contact with the piston 100. It can be seen that, if the the speed of recoil of the fork 89 (towards the right of FIGURE 1) increases, the pressure prevailing in front (to the left) of the piston 100 increases and this piston compresses the rings 105 and comes into contact with the piston 99. This closes the channels 106 and the oil can only pass through the annular play provided at the periphery of the piston 100. The recoil of the fork 89 is thus well braked whereas its advance is not braked, in particular by reason of the semi-positive coupling between the rod 101 and the stop 102.

Returning to the mechanism, including its lever 86, for motion transmission between the fork 89 and each feed mechanism 9, it is housed in the casing 82 which is connected directly to the breechcase 2 whereas the mechanism, having the lever 81 and the pawls 80, for the advance of the belt, is housed in the cover 71. The spindle 88 of the lever 86 is thus fixed to the casing 82 in which the passage 90 is formed, whereas the spindle 83 of the lever 81 is fixed to the cover 71. It will be understood that the coupling, by the projection 84 and the roller 87, between the two levers 86 and 81 permits opening and closing of the cover 71, for the transverse introduction of the cartridge belt, without any particular precaution.

Advantageously, the breech mechanism is arranged in a manner such that the rear of the motor member or fork 89, in the rest position illustrated in FIGURE 2, is located in front of the front face of the feed mechanisms. In other words, when the sleeve 15 is in its most forward position and when the shoulder 96 of the fork 89 is in abutment with the collar 46, the rear end of the one of the branches 89b that is located opposite a roller 85 does not penetrate into the corresponding passage 90. This permits the two feed mechanisms 9 to be rocked in the manner described above without the branches 89b of the fork 89 hindering this maneuver.

In the foregoing, a firearm has been described comprising at the interior of a breechcase 2, on the one hand, a sleeve 15 to which the barrel 16 of the firearm is fixed in a removable manner by a bayonet jont 17, and on the other hand, a nut 50 which is screwed on the front of the breechcase 2 and which serves to maintain the sleeve 15 in the longitudinal direction towards the front and in the transverse direction at the same time, connecting means 55 and 56 being provided between the part of the barrel 16 and/or the sleeve 15 situated at the front of the nut 50 and a zone situated at the rear of the sleeve 15 between this sleeve and the breechcase 2.

In this firearm, the sleeve is adapted to recoil with the barrel 16 with respect to the breechcase 2 and is guided in translation by the nut 50.

According to a third feature of the invention which could, should the occasion arise, be used in firearms in lwhich the breechcase 2 participates in the recoil and/or in which the connecting means are of another nature than a conduit for the gases, the sleeve 15 has two successive collars, namely a front collar 107, whose diameter is equal to the interior diameter of the nut 50 and which is disposed at the interior of the nut for maintaining the sleeve 15 transversely (with sliding, according to the embodiment represented), and a rear collar Iwhose diameter, greater than the diameter of the front collar 107, is equal to the interior diameter of the breechcase 2 and which is disposed to the rear of the nut 501 for maintaining the sleeve 15 longitudinally with respect to the nut 50 (by abutment) and transversely (lwith sliding) with respect to the breechcase 2. Preferably, this rear collar is the collar 46. Moreover, the interior diameter of the nut 50 is chosen suiciently large (in other words, the radial thickness of this nut sufficiently small) so that an intermediate element of the connecting means, and in particular the throttle device 56, passes through the front collar 107 without touching the nut 50.

The sleeve 15 is thus guided, at the front, by contact with the interior surfaces of the nut 50 (collar 107) and of the breechcase 2 (collar 46), and at the rear, by contact with the bore `98 of the ring 47. Its movement towards the front is limited by contact of the front face of its collar 46 with the rear face of the nut 50. A retractable locking device 108, having a ball or the like, prevents the nut from turning with respect to the breechcase 2.

Due to the arrangement of the nut 50 which has just been described, it can be seen that it is possible to screw it or unscrew it, with a view to dismantling or remantling the sleeve 15, Iwithout preliminary dismantling of the connecting means and more particularly, according to the example shown, of the throttle device 56.

In the foregoing, an ejection system has been briefly described which comprises an extractor 35 carried by the movable breech mechanism 1, and diametrically opposed, an ejector 33 carried by the breechcase 2 and actuated by the breech mechanism 1, by contact of the tail 33a of the ejector with the projection 25 of the breechlock 11.

More precisely, the ejector 33 comprises at the front a transverse striking surface 109 (FIGURES l and 5) for the rear edge of the empty cartridge case 110 to be ejected and it is controlled by the breech mechanism in the usual manner such that it presents the striking surface 109 into the trajectory of this rear edge during the recoil of the breech mechanism. To simplify the drawings, the lugs 13 of the breechlock 11 have been omitted in FIGURE 5.

According .to a fourth feature of the invention, |which can be applied whatever be the nature of the breech mechanism, and in particular, of its locking means (by rotation as described or with the aid of separate locks), the ejector 33 comprises, at the front of the striking surface 109, a projection 112 adapted to strike the lateral surface of the cartridge case 110 transversely, before the impact 'with the rear edge of the cartridge case. FIGURE 5 shows the cartridge case 110 which, still maintained at the top by the extractor 35 after having been struck by the projection 112, has begun its tipping movement in the direction of the ejection passage 7. It is only then that the striking surface 109 hits the rear edge of the cartridge case, with a relative speed which is decreased by the forward speed imposed on the part of this edge that the surface 109 strikes. In this manner, the violence of the impact is decreased and the ejection trajectory is stabilized.

The operation of the iirearm described above is the following.

When a cartridge is placed in the chamber 57 and when the breech mechanism arrives in the position of FIG- URES 1 and 2, the cartridge is red, which causes the recoil of the unit formed by the barrel 16, the sleeve 15 and the breech mechanism 1. By the rear of the collar 46 of the sleeve 15, the recoil damping springs 44 and the control springs 94 of the feed mechanisms are compressed and the pistons of the recoil dampers 51 and 52 are driven towards the rear. The springs 94 drive the fork 89 towards the rear with a speed regularzed by the dash-pot 97 and 99-105, whatever be the resistance to the traction of the belt in the one of the two feed mechanisms 9 that is in tiring position. According to the stroke of recoil of the firearm, the collar 46 of the sleeve 15 abuts or not against the shoulder 89e of the fork 89. By the one of its branches 89b which meets a roller 85, the fork makes the levers 86 and 81 of the feed mechanism in tiring position pivot, which puts a cartridge in position for introduction.

When the bullet has passed the gas outlet of the conduit 55, the gases pass through the throttle device 56, penetrate into the unlocking cylinder 53 and act on the front face of the piston or plunger 54. This piston or plunger 54 compresses the spring 58 and drives the breech mechanism casing 18 in `an accelerated movement. The casing 18, while recoiling, makes the breechblock 11 rotate in a manner such that it can -free itself from the sleeve 15. The residual pressure of the gases in the chamber 57 contributes to make the breechblock 11 recoil, which it does while compressing the counterrecoil spring 10, the breechblock 11 finally abutting at the end of its -stroke against the damping device 19. At the same time, the empty cartridge case is ejected in the manner described above.

The breech mechanism is then returned towards the front by the damping device 19 and the counter-recoil spring 10, drives the cartridge that was in position for introduction and introduces it into the chamber 57. The casing 18, which had been maintained at the rear of the breechblock 11 by the leaf-spring 38 during the reciprocation of the breech mechanism, is freed by the action of the inclined surface 40 and the spring 111 drives it towards the front, which, on the one hand, locks the breechblock 11 by making it rotate and then brings the point of the firing pin 21 into the cup-shaped recess 12 (new percussion).

During the forward return of the breech mechanism, the springs 44 restore their energy while bringing back towards the front the sleeve 15 and the barrel 16. The fork S9 is driven positively towards the front by abutment of the shoulder 96 against the collar 46 and is also driven in this direction by the springs 94. The damper 97 and 99-102 is inoperative during this forward stroke, for the reasons explained above (separation of the pistons 99 and 100, absence of positive coupling between the rod 101 and the abutment 102). On the contrary, the dampers 51 and 52 brake the recoil as well as the return to firing position of the unit formed by the sleeve 15 and the barrell 16.

Such a firearm has numerous and real advantages, in particular:

A reduced cumbersomeness, since the two feed mechanisms 9 are disposed on parts of the breech mechanism that are narrowed by a substantially rectangular cross-section;

A simple putting out of action of the retracted feed mechanism, since it depends only on the position of this feed mechanism;

A gain of energy in the driving of the feed mechanism into its firing position since the only members in motion are those which transmit directly the recoil energy to this feed mechanism;

A great facility of dismantling of the firearm due to the construction of the nut 50;

A great safety of operation due to the fact that all the moving members are housed at the interior of a Huid-tight breechcase.

Although the invention has been described with particular reference to a preferred embodiment, it should be understood that the invention is not limited thereto, and that various modifications and changes are possible without departing from the spirit and scope of the invention.

I claim:

1. A firearm of the type having a breechcase, a barrel cooperating with the breechcase and a breech mechanism movable longitudinally in the breechcase, at least between a loading position and a firing position, the arrangement wherein said breechcase has a substantially rectangular rear portion comprising a pair of opposing small sides and a pair of opposing large sides, one of the small sides having an ejection passage for the ejection of empty cartridge cases, at least one of said large sides having an opening for the introduction of new cartridges to be fired, a helical counter-recoil spring mounted in said breechcase to urge the breech mechanism toward said firing position, and wherein the portions of said large sides immediately adjacent said opening form guide surfaces for guiding the longitudinal movement of both the breech mechanism and the spring, said guide surfaces lying on a common geometrical cylinder of revolution about an axis extending in the same direction as the axis of the said barrel, the diameter of said cylinder being substantially equal to the outer diameter of the breech mechanism and of the said spring.

2. A firearm as claimed in claim 1 wherein both of said large sides have an opening for the introduction of new cartridges to be fired, and wherein the portions of said large sides immediately adjacent both said openings form said guide surfaces.

3. A firearm according to claim Z wherein the parts of the said large sides rearward of said openings are closed by coaxial curved parts, the interior surfaces of which lie on the said common geometrical cylinder of revolution whereby said internal surfaces further guide the movement of the said breech mechanism and the said counter-recoil spring.

4. A firearm according to claim 3, wherein the parts of the large sides between the said openings and that small side having the ejection passage are generally fiat, and wherein the distance between the interior surfaces of said generally flat parts is larger than the maximum diameter of the cartridges to be fired and smaller than the diameter of said common geometrical cylinder of revolution.

5. A firearm according to claim 3, wherein the said curved parts of the large sides extend rearwardly beyond the substantially rectangular portion to form two cylindrical sectors which are provided with bayonet lugs, the two cylindrical sectors being adapted to receive and to secure a generally cylindrical closing block which serves as a support for the rearward end of the said counterlrecoil spring which contains a breech mechanism damping device.

6. A firearm according to claim 2 including at least one spindle adjacent the exterior of one small side for pivotally mounting a pair of feed mechanisms, one adjacent each large side of the firearm, for alternative movement into a firing position, and a mechanism on the other small side for controlling the pivotal movement of the feed mechanisms about said spindle.

7. A firearm according to claim 1, wherein the forward end of said substantially rectangular portion of the breechcase is connected to a front part which has cylindrical and co-axial interior and exterior cross-sections, said front part receiving therein a sleeve, to which the said barrel of the firearm is removably attached, such that an annular space is provided between the exterior of the sleeve and the interior of the said front part, said annular space having mounted therein, (a) at least one control rod operatively connected to a recoiling part of the firearm and operable to control a feed mechanism for feeding cartridges to said opening, (b) damping devices for damping the recoil force and (c) an unlocking device operatively connected to a recoiling part of the firearm and operable to cause unlocking of said breech mechanism after the firearm has been fired.

8. A firearm according to claim 1 wherein the interior of the said substantially rectangular portion of the breechcase, rearward of the said opening includes, on the interior of said small sides, a sear device for holding the breech mechanism in a rearward position and an ejector for ejecting spent cartridges from the firearm.

9. A firearm according to claim 8 and further including on the interior surface of said small sides a resetting device for manually moving the breech mechanism to its rearward position.

References Cited UNITED STATES PATENTS 2,868,083 1/1959 Windstrup 89-199 BENJAMIN A. BORCHELT, Primary Examiner.

S. C. BENTLEY, Assistant Examiner. 

